Magnetic susceptibility of non-ellipsoidal samples is a long-standing problem in experimental studies of magnetism and superconductivity. Here the quantitative description of the Meissner-London response (no Abrikosov vortices) of right circular cylinders in an axial magnetic field is given. The three-dimensional adaptive finite-element modeling was used to calculate the total magnetic moment, m, in a wide range of London penetration depth, lambda, to sample size ratios. By fitting the numerical data, the closed-form universal magnetic susceptibility is formulated involving only sample dimensions and lambda, thus providing a recipe for determining the London penetration depth from the accurate magnetic susceptibility measurements. Detailed examples of the experimental data analysis using the developed approach are given. The results can be extended to the frequently used cuboid-shaped samples.
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